Biomedical subjects

G M Howard

Publications and source records attributed to G M Howard.

At least 19 recordsLinked to original sources

PubMed1983

Orbital arteriovenous malformation with secondary capillary angiomatosis treated by embolization with silastic liquid.

A 19-year-old Caucasian man developed signs of an orbital arteriovenous malformation, which was biopsied and then treated by embolization with a rapidly polymerizing silastic liquid. The biopsy from the initial specimen showed arteries and veins that were malformed with irregular elasticas and muscularis thicknesses, but the most curious feature was a secondary endothelial cell proliferation of such proportions as to simulate in various fields a capillary hemangioma of childhood. Approximately 50% of the bulk of the tumor was the result of the secondary endothelial cell proliferation, which we presume occurred in response to the irritative circumstances of increased intracapillary pressure from the high blood flow between the abnormal arteries and veins. Four years after the tumor was treated with the silastic liquid, it recurred and was again removed surgically. On this occasion, the histopathologic study of the tissues demonstrated a persistent secondary capillary angiomatosis, as well as chronic inflammatory reaction and granulomatous response surrounding the entrapped fragments of the polymerized silastic liquid.

Adult↗

PubMed1982

Histopathologic examination of a globe containing an intraocular implant.

A patient had both cataracts removed and a Copeland pseudophakos was implanted in one eye. Both globes were retained at autopsy for histopathologic study. The globe containing the implant did not show evidence of acute or chronic inflammation of the anterior segment, nor did it display signs suggesting secondary glaucoma. Some erosion of the iris pigment epithelium was present. In general, the globe appeared to tolerate the implant.

Aged↗

PubMed1978

Pulsating metastatic tumor of the orbit.

A 47-year-old white man in apparent good health had diplopia and swelling of the right upper eyelid. Ocular examination showed proptosis of the right eye, together with a large, pulsatile, collapsible mass simulating a vascular neoplasm and involving the right temple as well as the right upper outer quadrant of the orbit. Biopsy of the orbital tumor disclosed a clear-cell carcinoma compatible with a renal primary tumor; subsequent laboratory examination revealed the offending tumor in the left kidney. Renal carcinomas may metastasize to the globe or to the orbit before the primary tumor is recognized. Pulsatile exophthalmos acquired in middle life associated with significant bone destruction represents a constellation of findings most consistent with a metastatic tumor, probably renal carcinoma, caused by the exceedingly rich vascularization of these metastatic deposits.

Adenocarcinoma↗

PubMed1975

Sector hamartoma of the iris.

A 15-year old girl with a jet black-pigmented lesion on the anterior surface of the upper nasal quadrant of her iris was followed up for 12 years, during which interval growth of the lesion was documented. Histopathological evaluation of the excised segment of the iris revealed a pigment epithelial proliferation originating from posterior pigment epithelium. Additionally, there was a band of spindle shaped smooth muscle cells in the posterior stroma and a zone of plump melanocytes in the anterior stroma beneath the proliferating pigment epithelial cells. This combination of abnormalities is thought to represent a benign hamartomatous maldevelopment of the involved sector of the iris rather than a true neoplasm. Such an elaborate dysgenesis is unlike the more modest melanocytic hamartomas of the iris associated with the phakomatoses.

Adolescent↗

PubMed1975

Electron microscopic diagnosis of medulloepithelioma.

A 20-month-old boy with a ciliary body tumor presented with two white flocculi floating in the anterior chamber of his left eye. This material was examined by electron microscopy. Both the clinical appearance of the tumor and the ultrastructural findings suggested the diagnosis of medulloepithelioma. The flocculi contained tumor cells forming lumina and displaying neuronal-type cilia, neurotubules, and a complex band of apical desmonosomal junctions. Since the last finding is not present in retinoblastoma rosettes in the absence of fleurette differentiation, it distinguishes medulloepithelioma from retinoblastoma. The electron microscopic diagnosis has permitted a trial period of conservative cryotherapy directed at the tumor and the associated glaucoma. The electron microscopic characteristics of the tumor favor the neuroepitheliomatous and neuroblastic differentiation of medulloepithelioma rather than ependymal differentiation.

Anterior Chamber↗

PubMed1975

Leiomyoma and leiomyosarcoma of the orbit.

Comparison of the clinical and pathologic features of two orbital leiomyomas, two leiomysarcomas, and one embryonal rhabdomyosarcoma showed the leiomyomas occurred in young individuals and the leiomyosarcomas in older patients. The histopathologic diagnosis rested on the intense cytoplasmic eosinophilia and nostriated longitudinal cytoplasmic filaments demonstrated by means of the trichrome stain. The leiomyosarcomas disseminated 15 months and seven years after their orbital presentations. The treatment of both leiomyoma and leiomyosarcoma is surgical. Leiomyomas are encapsulated growths that may have small satellite nodules projecting from the main tumor mass; thus, a margin of normal tissue should also be excised, lest a small lobulation be left behind to serve as the seed for a late recurrence. Once the diagnosis of leiomyosarcoma has been made, and no evidence of metastasis has been found after a thorough systemic evaluation, the orbit should be exenterated, because the tumor is unencapsulated and liable to widespread dissemination. Rhabdomyosarcoma has a much more fulminant course than leiomyosarcoma, and especially more so than that of leiomyoma of childhood. The histopathologic diagnosis of a malignant smooth muscle tumor in a child should always be questioned, since embryonal rhabdomyosarcoma is a much more likely diagnosis.

Adolescent↗

PubMed1975

Kaposi's sarcoma of the conjunctiva.

A 75-year-old man with known Kaposi's sarcoma of three-years' duration developed chronic hemorrhagic thickening of the conjunctiva. Biopsy demonstrated histopathologically that the conjunctiva thickening represented sarcoma involvement. Although surgically untenable, the conjunctival lesion responds satisfactorily to radiotherapy.

Aged↗

PubMed1974